Field
This disclosure relates generally to decoders, and more specifically, to a quaternary decoder that decodes quaternary logic states.
Related Art
Some processors use dedicated binary inputs for selection of their boot-up sources and boot-up modes. Dedicated binary inputs are preferred due to their convenience for the user, rather than multiplexed I/O (input/output) that requires external circuitry to change the multiplexed I/O from the boot selection function to other functions. Additionally, multiplexing binary inputs with a bus causes extra loading on the bus, which is detrimental especially for high-speed busses prevalent on modern processors. However, these dedicated binary source- and mode-selection inputs tie up a large footprint of valuable input/output (I/O) area that could otherwise be used for other functions. Additionally, processors having multiple boot-up sources and multiple modes for each source require a large number of binary inputs, which in turn requires the use of packages with larger ball counts to accommodate the source- and mode-selection inputs.
The present invention is illustrated by way of example and is not limited by the accompanying figures, in which like references indicate similar elements, unless otherwise noted. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.